Seems simple at first but it is actually very challenging because once you place a triangle, there is no changing it. I would've liked if you were able to see the next piece coming up after the current one to simplify things but so be it. This is one of those games that it is easy to get lost in and, if you're like me, determination makes you want to keep playing to try to complete the puzzle. That's a compliment to the creator.

Many thanks to zuzumber and GGOTD for this.